CONFIDENTIAL EE/DEC 2016/EPO640/644 QUESTION 1 a) With the aid of a suitable diagram with labels, describe the four quad

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Confidential Ee Dec 2016 Epo640 644 Question 1 A With The Aid Of A Suitable Diagram With Labels Describe The Four Quad 1 (40.19 KiB) Viewed 43 times

CONFIDENTIAL EE/DEC 2016/EPO640/644 QUESTION 1 a) With the aid of a suitable diagram with labels, describe the four quadrants of operation of a motor drive? How does this apply to motion control system? (10 marks) b) Compare the merits and demerits of DC drives and AC drives (5 marks) c) A 24hp DC Shunt motor is running full-load at 900 rpm at armature voltage 600V. The armature and field resistances of the motor are 10 and 800 Q respectively. The efficiency of the motor at full load is 90%. 1) If the motor is braked by dynamic braking, calculate the value of the braking resistor that will limit the initial braking current to 150% of the rated value. it) If the motor operates in regenerative braking mode at speed of 1000 rpm calculate the line current and braking torque. Sketch the circuit for counter-current braking (by reversing the supply voltage). Determine the braking resistor that will limit the initial braking current to 140% of the rated current. (10 marks) 1)